Allergic bronchopulmonary mycosis (ABPA)
Allergic bronchopulmonary mycosis is a pulmonary hypersensitivity disorder caused by allergy to fungal antigens that colonize the tracheobronchial tree. It usually occurs in atopic asthmatic individuals who are 20–40 years of age or those with cystic fibrosis, in response to antigens of Aspergillus species. For this reason, the disorder is commonly referred to as allergic bronchopulmonary aspergillosis (ABPA).
Aspergillus is a type of fungus (also referred to as a mold), that is commonly found in the environment. It can be found in the soil, dust, water, and rotting or decaying vegetation (like dead leaves or compost piles), marijuana, and some foods and ground spices. The fungus forms into spores which are very small particles that can float in the air. Most people inhale its spores from the air, but do not have any problems from being exposed. In most cases, the fungus can live in the mucus in the breathing tubes (airways). This is called colonization.
Having Aspergillus in your airways does not mean you have or will have a sudden (acute), and serious infection by this fungus. Our immune system usually helps protect the body from infections like these.
In some people who have a weakened immune system, Aspergillus can get into the lungs, causing an acute infection. However, in a few cases, this exposure to Aspergillus triggers an allergic immune response without invading the tissues that leads to ABPA (allergic bronchopulmonary aspergillosis).
Common signs and symptoms of ABPA
A person with ABPA will have some or all of the following symptoms:
- Coughing frequently
- Coughing up mucus plugs that may be brown in color. You may also cough up blood (called hemoptysis).
- Difficulty exercising
- Shortness of breath or feeling like it is difficult to get air into or out of your lungs.
- Chest pain or tightness
- Fever that goes away then comes back
ABPA with asthma
ABPA can be a rare cause of poorly controlled asthma, occurring in less than 1% of asthma patients. A person with asthma who develops ABPA has difficulty controlling their asthma despite using many medications. Because ABPA can be treated, it is sometimes considered in cases of poor asthma control.
ABPA with cystic fibrosis (CF)
Cystic fibrosis is a genetic disease that can affect the lungs. ABPA can be seen in 1-15% of people with CF. ABPA is considered when a person with CF has worsening symptoms and lung function not responding to other CF therapy.
Primary criteria for the diagnosis of ABPA include
- a clinical history of asthma or cystic fibrosis;
- elevated serum total IgE levels (typically greater than 1000 international units/mL; a value less than 1000 international units/mL may be acceptable if all other criteria are met);
- immediate cutaneous hypersensitivity to Aspergillus antigens or elevated serum IgE levels specific to Aspergillus fumigatus; and
- at least two of the following:
- precipitating serum antibodies to Aspergillus antigen or elevated serum Aspergillus IgG by immunoassay,
- radiographic pulmonary opacities consistent with ABPA, or
- peripheral blood eosinophil count greater than 500 cells/mcL.
High-dose prednisone (0.5–1 mg/kg orally per day) for at least 2 weeks is the initial treatment of choice. Depending on the clinical situation, prednisone dose can then be reduced or converted to every other day and slowly tapered over 3–6 months.
Relapses are frequent, and protracted or repeated treatment with corticosteroids is not uncommon. Patients with corticosteroid-dependent disease may benefit from itraconazole (200 mg orally three times a day for 3 days, followed by twice daily [with food if the capsule